Wafer-Level Packaging (WLP) refers to the technology of packaging an integrated circuit at wafer level, instead of the traditional process of assembling the package of each individual unit after wafer dicing. WLP is closest to being a true chip-scale packaging (CSP) technology. Wafer-level packaging integrates wafer fabrication, packaging, test, and burn-in at wafer level, and streamlines the manufacturing process. Wafer-level packaging extends the wafer fabrication processes to include device interconnection and device protection processes. The use of WLP has dramatically grown as a result of its advantages in size, performance, flexibility, reliability, and cost over other packaging methods.
One of the challenges with WLP arises from the limitation of number of contacts and/or the contact area. Methods to overcome these limitations result in increased production costs and/or poor reliability and yield loss. Hence, what are needed are methods and apparatus for flip chip packaging that is not only cost effective but allows for improved contact formation.